"What happened here in Colombia is being investigated by the director of the Secret Service," Obama said. "I expect that investigation to be thorough and I expect it to be rigorous," the president told reporters in his first public reaction to the controversy. "If it turns out that some of the allegations that have been made in the press are confirmed, then of course I'll be angry."

But Kessler said there's no need for an investigation.

"There's nothing to wait for," he said. "The action that's needed is replacement of the Secret Service director because it's really President Obama's life that is at stake."